A vehicle seat or a seat of a sofa and the like used indoors is typically constituted by a seat pad and a surface material: the seat pad is made of foam synthetic resin, such as flexible polyurethane foam or semirigid polyurethane foam; the surface material is attached to a front surface of the seat pad.
In some cases, in order to prevent generation of unusual noise or damage to the seat pad when the seat pad is in contact with a seat frame, a reinforcing member made of nonwoven fabric and the like is provided on the back surface of the seat pad (i.e., a surface opposite to a person seated on the seat) (Japanese Patent Publication 2005-237491 A). For the molding of this seat pad with a reinforcing member using a mold, a foam synthetic resin material is made to foam in the mold to which the reinforcing member is attached before molding. In this manner, a seat pad with a reinforcing member integrated in the back side thereof is molded.
In this case, the reinforcing member is fixed to the inner surface of the mold by the following methods. For example, a magnet is provided in the mold and a magnetic body which is attracted by this magnet is provided in the reinforcing member: the reinforcing member is fixed to the inner surface of the mold by causing this magnetic body to be attracted by the magnet. Alternatively, the mold is made of a magnetic metal material which is capable of being attracted by the magnet and a magnet is attached to the reinforcing member: the reinforcing member is fixed to the inner surface of the mold by causing this magnet to be attracted by the inner surface of the mold (Japanese Patent Publication 2001-252930 A).